Finely-divided-fuel-burning furnace construction



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FINELY DIVIDED FUEL BURNING FURNACE CONSTRUCTION Filed June 16, 1925 2 Sheets-Sheet 1 aduc/nto@ NOV. 1l, 1930. w, R, WOOD 1,781,310

i FINELY DIVIDED FUEL BURNING FURNACE CONSTRUCTION Filed June 16, 1925l 2 Sheets-Sheet 2 Suva/nto@ Wy@ *WML 5513 Wmv/13S Patented Nov. 11,1930

UNITED 'STATES PATENT oFFlcE WILFBED R. WOOD, OF LONDON, ENGLAND, ASS-SIGNOR T INTERNATIONAL ClVIIYB'U'S-` '.L'ION ENGINEERING CORPORATION, l OF NEWl YORK, N, Y., A CORPORATION 0F DELAWARE FINELY-DIVIDED-FUEL-BURNING FURNACE CONSTRUCTION Application filed Jnne 16,

This invention relates to furnaces, and itl is particularly useful where the fuel to be burnedis in finely divided form, such, for example, as powdered coal. g One of the primary objects of my invention yis to provide what may be termed .an improved hollow wall construction having the advantages hereinafter set forth.

Another object of the invention is to lo- .10 cate evaporating surfaces within th'e combustion chamber so as to define combustion space thereof, such evaporating surfaces co-operating to provide a hollow wall.

How the foregoing, together with such other objects as may 'hereinafter appear, or

combustion chamber has an outlet 7 over which is located the boiler 8, which, becauseof the large area of evaporating surface ex posed directly to radiant heat, as will hereinafter appear,may be of much smaller size and much less number of tubes than-standf ard. The powdered fuel is preferably introduced in a downward direction thru a suspended arch 9 by means of burners 10, 4o preferably arranged in a. row, which burners tion chamber to one side of the outlet 7 ,in consequence thereof, the fuel and flame stream takes a U shape course thru the combustion 45 chamber with combustion substantially completed before the -tubes 8 are reached. The fuel with carrying air is supplied to the' burners by the pipes 1l and additional air for combustion-say in the neighborhood of from 2O to 30 per centr-is introduced. thru direct the fuel downwardly into the combus-` 1925. Serial No. 37,425.

the burner castings, as is understood in this art.

The front wall construction, as may also be the side wall construction, is as follows:

Suitably supported buck stays 12 cari' a shell 13, preferably metallic, which shell is lined with a suitable insulating materialill, which material need not necessarily be highly refractory.

Spaced away from the insulating lining is a wall B, which is'eomposed of a plurality of tubes 15, which tubes have'lon itudinal fins 16 secured thereto, preferably y welding. The tubes are pre erably arranged as shown in Fig. 2 with the edges lofthe tins of adjacent tubes substantially abutting, whereby a wall is formed. rIhe use of tin tubes makes it possible to space the tubes sufficiently so that there will be a proper ligament (i. e. metal between tubeholes) in the upper header 17 vand the lower header 18, besides which, in addition to helping to form the wall, they conduct heat to the tubes, the whole constituting a very effective evaporating medium. At suitable intervals the tins are interrupted to provide inlet slits or openings 19 where it is desirable to introduce additional air for combustion. In this case, suilicient air inlets '19 are provided to make up the deficiency in the air required for combustion.

The air which flows thru the openings 19 is supplied as follows to the space between the tube wall B and the insulating lining. The side walls 20 are hollow, the space being divided into a plurality of horizontal compartments 21, which have their forward ends in connection with the space between the tube wall and the insulating lining. The compartments 21 are open at the rear ends for admission of outside air, the inlets being controlled by the dampers diagrammatically indicated at 22. The space between the tube wall and the insulating lining is also divided into horizontal compartments 23, registering with the compartments 21 by Ameans of the refractory slabs 24 which have a width greaterthan the width of the space between the tube wall and the lining. Their outer edges are supported by means of studs 26 or other ing medium.

wardly and upwardly and have their rear.

suitable supporting members, and their inner edges are notched as at 27 to tit the tubes 15, the inner edges resting against thetubes 15 and also, if desired, against the tins. By virtue ot' their length, the slabs when assembled occupy the position shown in Fig. l and they must of necessity lremain, in place.

Since they form no bond or tie of any kind between the inner and outer wall members, and since the tube wall is preferably suspended from the header 17, it will be seen that the inner wall portion can expand and contract readily without imposing any strains.

The insulating lining, the slabs andthe studs are fully protected from the heat by virtue of the high rate of absorption ot' the tube wall, in which connection it is to be noted that while the air which is drawn thru the space in the walls is preheated, itv does not reach a detrimentally high temperature. By suitable control of the dampers 22 air may be regulably admitted to suit all rates ot `firing. l s

Connected into the header 1S are a plu` rality of tubes 28 constituting a water screen C located in the bottom of the combustion space over the ash hopper 29. The function of this screen is to reduce the temperature ot the refuse particles precipitating therethru to the ash hopper below the point at which the depositcoalesces into a mass or slab. the deposit being thus readily removable. The screen also serves as a very effective eva porat- The tubes 28 are inclined rearends connected by suitable connections 30 to the lower ends of the tubes 31, forming a rear wall screen D which tubes may also be provided with fins. In back of the tubes 31 is a bridge wall structure composed of t-he buck stays 32,' the shell 33, insulating lining 34 and refractory lining 35, the wall being locally thickened in the region of the lower` ends of the tubes 31 and terminating where the tubes 31 pass out thru the wall 36, which is carried on the structural work 37. IlVherel the tubes 28 pass thru the bridge wall and where the tubes 31 pass thru the wall 36, sand fillings 38 are provided to makev provision for'possible shifting of the tubes under operating conditions. The upper ends of the tubes 31 are connected into the header 39 which is connected in turn to the steam space by suitable connections 40. Downcomer tubes 41, suitably connected into the boiler and of a size sufficient to convey the properV amount of water, supply the header 18 and the tubes 15 constitute upcomers, as do the tubes 28 and 31. In this connection the header 17 is suitably connected to the steam space by a tube or tubes 42. e

It will be seen from the foregoing thatI have a very simple front hollow wall construction and a simple rear wall construction,

and an arrangement of tubes within the combustion chamber which takes care of expansion and contraction, such arrangement being very simple and composed of a minimum number of parts.

The tubes defining the combustion space are subject to radiant heat and absorb an enormous quantity of heat and are thus proportionately effective for evaporation.v In this connection the supplying of preheated air for combustion prevents interference with proper combustion which might otherwise be the case owing to the tendency ofthe tubes to lower the temperature within the furnace. The rear, or bridge wall, can be made of very light construction as it is fully protected by the screen D, and the outer portion of the front wall can also be made of much more simple construction than ordinary.

I claim:

1. In a combustion chamber for burning finely divided fuel, a hollow wall comprising an outer wall portion, and an inner wall portion spaced away therefrom and comprising evaporating means, means. for dividing the Y space therebetween into compartments and means independent of one of said walls providing a support for said space dividing means.

2. In a combustion chamber for burning finely divided fuel, a hollow wall comprising ail outer wall portion, and an inner Wall p0rtion spaced away therefrom and comprising evaporating means, there being relative movement between the inner and outer Wall portions when expanding and contracting,

and members dividing the space between wall portions into substantially horizontal compartments, said members being carried by one wall portion and leaning against the other.

In testimony whereof, I have hereunto signed my name.

WILFRED R. 'WOOD ist, 

